This is a fun little game and in many ways it is an improvement on the first, but I can't help but think they could have done more with it.
Firstly, there is no story, this is solely a beat-em-up game with a few mini games on VS mode. It's pretty unusual these days for a beat em up game not to have a story running through it or even a full story mode. They missed out there, especially since the TV show probably draws in most buyers.
Repetitiveness is also an issue, again in part due to there being no story. But there were also times playing through where I ended up fighting the same opponent like 3 times in a row...that's happened on several occasions and really shouldn't!
The unlockable characters are okay. Unfortunately most of them are Mega level bosses, which are fun to play as every once in a while, but they're so powerful, you're not really challenged if you play as them. I would have much rather have seen rookie unlockables that could digivolve. The only evolvable unlockables we get are BlackAgumon, BlackGabumon and BlackGuilmon, which as the names suggest are just recoloured versions of their respective offset characters...even most of their attacks are just recolourings.
There are good things though. The game play flows much more smoothly than the previous game, there are more characters. The arenas are interactive and you can throw objects, pick up items etc. Most digimon can digivolve twice and there are quite a few mini games to play on VS mode.
This game is worth getting, there are just a lot of missed opportunities.